Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

<image>

In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
inline int next_int() {
  char c;
  while (c = getchar(), c < '0' || c > '9')
    ;
  int r = c - '0';
  while (c = getchar(), c >= '0' && c <= '9') r = r * 10 + c - '0';
  return r;
}
int main() {
  std::ios::sync_with_stdio(false);
  int n, m;
  int arr[105][105];
  int row[105];
  int col[105];
  while (cin >> n >> m) {
    int ans = 0;
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < m; ++j) {
        cin >> arr[i][j];
      }
    }
    if (n <= m) {
      for (int i = 0; i < n; ++i) {
        row[i] = 0x3f3f3f3f;
        for (int j = 0; j < m; ++j) {
          row[i] = min(row[i], arr[i][j]);
        }
        if (row[i]) {
          for (int j = 0; j < m; ++j) {
            arr[i][j] -= row[i];
          }
        }
        ans += row[i];
      }
      for (int j = 0; j < m; ++j) {
        col[j] = 0x3f3f3f3f;
        for (int i = 0; i < n; ++i) {
          col[j] = min(col[j], arr[i][j]);
        }
        if (col[j]) {
          for (int i = 0; i < n; ++i) {
            arr[i][j] -= col[j];
          }
        }
        ans += col[j];
      }
    } else {
      for (int j = 0; j < m; ++j) {
        col[j] = 0x3f3f3f3f;
        for (int i = 0; i < n; ++i) {
          col[j] = min(col[j], arr[i][j]);
        }
        if (col[j]) {
          for (int i = 0; i < n; ++i) {
            arr[i][j] -= col[j];
          }
        }
        ans += col[j];
      }
      for (int i = 0; i < n; ++i) {
        row[i] = 0x3f3f3f3f;
        for (int j = 0; j < m; ++j) {
          row[i] = min(row[i], arr[i][j]);
        }
        if (row[i]) {
          for (int j = 0; j < m; ++j) {
            arr[i][j] -= row[i];
          }
        }
        ans += row[i];
      }
    }
    bool type = false;
    for (int i = 0; i < n; ++i) {
      for (int j = 0; j < m; ++j) {
        if (arr[i][j]) {
          cout << "-1" << endl;
          type = true;
          break;
        }
      }
      if (type) break;
    }
    if (!type) {
      cout << ans << endl;
      for (int i = 0; i < n; ++i) {
        for (int j = 0; j < row[i]; ++j) {
          cout << "row " << i + 1 << endl;
        }
      }
      for (int i = 0; i < m; ++i) {
        for (int j = 0; j < col[i]; ++j) {
          cout << "col " << i + 1 << endl;
        }
      }
    }
  }
  return 0;
}